Gyroscopic flight indicating instrument



March'Z, 1948. T. o. SUMMERS,"JR

GYROSCOPIC FLIGHT INDICATING INSTRUMENT Filed Dec. 8, 1942 3 Sheets-Sheet 1 mmlllll ll ll I v INVENTOR. flaws d flan/1 15,65 r/k.

ATTORNEY.

March 2, 1948.

'IIII/IIIIII/II I/l/I/II/II/IIIIII/l/ Hillll T. o. S-UMMERS, JR 2,437,175

:GYROSCOPIC FLIGHT INDICATING INSTRUMENT Filed Dec. 8, 1942 s Sheets- Sheet 2 ,,,,,,,mu,"M 1

42 y o I INVENTOR. 22 02/45 dim/M525 J6.

ATTORNEY.

BY I

March 2, 1948. T. o. SUMMERS, JR

GYROSCOPIC FLIGHi INDICATING" INSTRUMENT Filed Dec. 8, 19 42 5 Sheets-Sheet 3 EEEE \ III/11111171171 a 1 1 III, IIIII, "11,11,111

IlIl/IIIIIII 111111!!! V INVENTOR'. Jim/v45 0, jaw/5R5 we.

ATTORNEY.

Patented Mar. 2, 1948 GYROSCOPIC FLIGHT INDICATING INSTRUMENT Thomas 0. Summers, Jr., Los Angeles, Calif. I

Application December 8, 1942, Serial No. 468,189

'7 Claims.

1 This invention relates to gyroscopic indicators and more particularly to aircraft instruments for determining spacial orientation.

An object of my present invention is to provide a flight indicating instrument which in-.

cludes means actuated by centrifugal force for indicating severity of turn, and which represents an improvement over instruments of this nature already in common use in that it is not aifected by yawing of the craft carrying the instrument.

Another object is to provide an instrument for indicating severity of turn as described, and a bank indicator so cooperatively associated therewith as to be capable of giving the pilot an immediate indication not only of the degree at which his ship is banking, but also, in the event that the degree of bank is not that which will enable the ship to negotiate the turn then being made, in just what manner and to what extent the banking of the craft should be corrected.

A further object is to provide a flight indicating instrument capable of indicating turn, degree of bank actually being experienced, degree of bank appropriate to a turn being negotiated, and attitude of the ship about a transverse axis, and wherein the indicating media by the observation of which the pilotcan inform himself regarding all four of these functions are arranged in a single, easily read group, in contradistinction to more conventional'practice which has necessitated the observation of several independently operating instruments disposed at relatively widely spaced positions upon the instrument panel in such a manner as to preclude their simultaneous observation and comparison by the pilot.

A further object in this connection is so to design and correlate the mechanism for performing these several functions that it is of unitary construction and capable of being mounted in a single housing of substantially the same size and shape as that conventionally employed for a single gyroscopic instrument such as an artificial horizon, and thereby not only reduce the number of separate instruments which must be checked constantly by the pilot, but also eifect a valuable saving in weight and space on the instrument panel.

Another object is to. present an instrument of the character described wherein the bank-indicating reference is damped in such a manner as to prevent its uncontrolled and sudden movements.

f. The invention possesses other objects and features of advantage, some or which, with the fore- 2 going, will be set forth in the following description of the preferred forms of my invention illustrated in the drawings accompanying and forming part of the specification. It is to be understood however, that I do not limit myself to the showing made by the said drawings and description as I may adopt variations of the preferred forms within the scope of my invention as set forth in the claims.

Referring to the drawings:

Figure 1 is face view of a flight-indicating instrument embodying the principles of the present invention with the several indicating media thereof in their respective positions to indicate straight and level flight.

Figure 2 is a view similar to Figure 1, drawn to a reduced scale but with the indicating media showing tail low position;

Figure 3 is a similar view showing tail high position.

Figure 4 is another similar view indicating a properly banked left turn.

Figure 5 is another similar view showing an improperly banked condition, i. e., the ship is tilted to the left but is not experiencing a turn and therefore is experiencing or is apt to develop a side slip.

Figure 6 is still another similar view wherein the indicating media show that the ship is turning to the left without, however, being properly banked.

Figure 7 is a horizontal, medial sectional view, the plane of section being indicated by the line A--A of Figure 1 and the direction of view by the arrows. In Figs. 1 through 6, the airplane tail simulating indicia is fixedly mounted on the instrument housing. In Fig. 7, this indicia isadjustably mounted in the instrument housing.

Figure 8 is a transverse, vertical sectional view taken just behind the transparent face of the instrument, the plane. of section being indicated by the line 88 of Figure 7 and the direction of view by the arrows.

Figure 9 is an enlarged detail view in horizontal section taken upon the line 99 of Figure 8 with the direction of View as indicated, to show the construction of the pendulum indicator and damping mechanism associated therewith.

Figure 10 is a transverse, vertical sectional view taken upon the line Iii-l0 of Figure 9 with the direction of view as indicated.

Figure 11 is a view similar to Figure 10 taken, however, on the line l|-|l with the direction of view as indicated. V

Figure 12 is an exploded view in perspectiv 3 showing the relative arrangement of parts Which comprise the pendulum indicator and its damping mechanism.

That modification of the flight indicating instrument of the present invention Which has been chosen for illustration and description herein is shown as being encased in a suitable housing it adapted for mounting upon the instrument panel of an airplane, as by mounting screws H extending through lugs H3 which are provided upon front 29 of the housing. The front 19 also is provided with a transparent window 2| through which may be observed the indicating media, indicated in their entirety at 22.

The mechanism for operating the indicating media 22 comprises a gyroscope 23 supported for universal movement by means of a gimbal 2i mounted in bearings 2 2 and 28. In order to leave the indicating media 22 unobstructed and thus permit their facile observation through window 2%, I prefer to mount the gimbal 27 in such a manner as to leave the end of the operating structure which is proximal to the window 2! entirely free and clear and therefore the preferred construction employs a gimbal mounting wherein the two spaced bearings which carry the gimbal 2i are both disposed at the opposite end of the instrument. For a more complete disclosure of this type of gimbal support reference may be had to my co-pending application, Serial No. 457,730, filed September 9, 1942, now Patent No. 2,423,269, issued July 1, 1947. Suffice it, therefore, for the purpose of the present disclosure to explain that air is supplied to the gyroscope 23 to effect rotation of its rotor 28 by means of a passageway 29 in the gimbal 2? and leading from a packed joint 2Q arranged co-axially with respect to the bearings 26 and 26, as also explained in greater detail in my said co-pending application. Atmospheric air is supplied to the joint 29 through a screened entrance opening 31 and an associated passageway 32 leading therefrom through the bracket which supports the bearings 24 and 2t and to the joint 29. The gyroscope 23 is supported in the gimbal 21 through the expedient of a pair of axially aligned pins 33 and 34 which are revolubly supported by bearings in gimbal 21. One of these pins, say the pin 34, is of hollow construction as indicated at 35' to establish communication between the passageway 29 in the gimbal 2'! and another passageway 35 in the rotor-bearing casing 36 of the gyroscope 23 whereby the air is supplied to the orifices 3'! which direct their jets tangentially against buckets 38 arranged on the periphery of the rotor 28 of the gyroscope 23, and thereby effect spinning of the rotor 23.

The parts are so proportioned and arranged that the entire structure supported by the gimbal 2! is in substantially neutral equilibrium; and for the purpose of maintaining this structure with the axis of spin of the rotor 28 in pro-selected position, a suitable erecting mechanism M is cooperatively associated with the gyroscope 23, thereby presenting a gyro vertical construction d2. Although any suitable type of erecting mechanism may be employed, for the sake of accuracy and dependability of operation and convenience of installation, I prefer to use one of the type disclosed in my co-opending abandoned application, Serial No. 463,050, filed October 23, 1942. However, since the details of construction and operation of the erecting mechanism form no portion of the present invention,

the following brief discussion thereof will suffice for the purpose of the present disclosure:

Operation of the erecting mechanism to cause it to perform the function of maintaining the gyroscope in pre-selected position is attained by means of a plurality of ports (not shown) so arranged that they direct jets of air in such directions that the reactive forces of those jets act upon the housing of the gyroscope to exert erecting torque thereagainst and thus cause the gyroscope to precess; and the ports are separately regulated in such a manner that each becomes operative whenever the gyroscope deviates from verticality in such direction that the reactive force of its jet is in the proper direction to correct the deviation. It is convenient, therefore, to operate the erecting mechanism 4! by the same air as that which drives the rotor, particularly so since the erecting mechanism is mounted directly upon the bottom of the rotor-bearing casing 36, so that as the air escapes the casing it passes directly into the erecting device where it is passed to the torque-developing ports. This double purpose flow of air through the gyro vertical s2 is induced by so arranging the torquecleveloping ports that they discharge from the housing of the erecting mechanism into the interior of the main housing it, where a partial vacuum is maintained by means of an exhaust tube 43.

The indicating media 22 include a pendulum indicator 51 which is carried by the rotor-bearing casing 33 within a suitable chamber 52 which is rigid with the rotor bearing casing 38 and therefore is stabilized by the gyro vertical 62 against moving with the airplane when the latter experiences pitching or rolling. The pendulum indicator 5! ismounted for swinging movement about an axis which coincides with the major gimbal axis, i. e., about the axis of the bearings 2E, 26. Referring to Figs. 9 through 12, the chamber 52 is conveniently formed of a substantially cylindrical housing 53 the back Wall 56 of'which is removably secured in position as by a snap ring 56 (see Fig. 9). The back wall E f! has a stud 5'? formed centrally thereon threaded into the forward side of the rotor bearing casing 3%, a lock nut 58 being provided to anchor the parts in selected position. Forward of the back wall 54 and spaced slightly therefrom by a resilient sealing gasket 59 is a thin and consequently relatively flexible closing partition (ii; and forward of this partition 6! and similarly spaced therefrom as by a gasket 62', is a relatively rigid partition 63. A disc as is spaced forward of the partition 53 by a relatively wide, annulus 56; and in front of the disc i i and separated therefrom by another sealing gasket 5? is a disc 88 of glass or other suitable transparent material which is spaced from an inwardly extending flange d8 of the housing 5 2 by a sealing gasket H.

The flexible partition El and the transparent disc 58 cooperate to confine a suitable liquid E2 within the housing The reason for using a thin member for the partition Kit is that it permits expansion of the fluid "[2 in conformity with temperature fluctuations. Toward this same end, the partition is provided with preferably a plurality of apertures A pin it is mountedcentrally and rigidly upon the partition 63 and extends forward therefrom to provide a journal support for a stub shaft Tl" upon the forward endof which the pendulum indicator 5i is rigidly'secured. The stub shaft 11 extends through a centra1 aperture 18 in the partition 54 so that whereas the pendulum indicator 5| is disposed in front of the partition 64 the after end of the stub shaft 1'! is behind that partition. Hence, a pendulous weight 19 which is rigidly secured to the after end of the stub shaft 78 is concealed from view through the window 68 by the partition 64 which serves therefore as a mask leaving only the pendulum indicator 5| visible. The pendulous weight 19 is substantially sector shaped with a radius only slightly less than the inside radius of the spacing annulus 65, with the result that when the pendulous mass 19 swings about the axis of the pin 16 it urges the fluid 72 to move within the housing 53. Such movement of the fluid however, is resisted by a baflie 3| which conveniently takes the form of a wedgeshaped member extending radially inwards from the spacing annulus 65. For the sake of convenience this spacing annulus 65, instead of being a complete ring, is split to leave an opening 8'2 at the upper portion thereof within which the baffle 8| is gripped so securely when the annulus 65 is pressed into the housing 53, that retention of the baflie 8| in desired position is assured.

Thus it may be seen that although the pendulum indicator 5| of itself is not necessarily pendulous, the pendulous mass is which is rigidly connected thereto by means of the stub shaft 11 causes the pendulum indicator 5| to move in exactly the same manner as though the indicator 5| itself were pendulous. However, such movements of the indicator 5| and the mass l9 are damped because of the fact that the mass 79 is immersed in the fluid "l2, and because of the further fact that the movement of the fluid 12 within the housing 13 is restricted by the bafiie 8|. The indicator 5| is so positioned upon the stub shaft 'i'l that it extends vertically when the mass i9 hangs with its center of gravity directly below the axis of the pin 15. Consequently the assembly of indicator 5|, shaft Ti and mass 19 are sensitive to acceleratory forces exerted in a transverse direction, such as those caused by centrifugal action when the airplane on which the instrument is mounted negotiates a turn.

At least two purposes are accomplished by damping of movements of the mass 19 and its indicator 5|. One of these purposes is that of making the indicator 5| more nearly dead heat, i. e., minimizing the tendency for the indicator to hunt its proper indicating position as by gradually settling thereon by moving back and forth therepast with oscillations of gradually decreasing amplitude. The other purpose accomplished by damping is to minimize the tendency for indicator 5| to move from its vertical, zero reading position by transverse forces of such short duration that they are of no particular significance as far as navigation of the plane is concerned.

For example, the described damping of the mass 19 will prevent the indicator 5| from moving to any material extent as the result of yawing of the craft, thus enabling the pilot to rely upon the pendulum indicator 5! to indicate only those movements of the plane which actually are coincident with its deviation from straight line travel. That is to say, when the airplane on which the instrument is mounted actually negotiates a turn, the pendulous mass 19 will be thrown toward the outside of that turn by centrifugal force, thus causing the stub shaft 11 to turn, carrying with it the pendulum indicator 5| which thus will be caused to assume an oblique position, as shown in Figures 4 and 6. Moreover, the extent of movement of the mass 19 and its pendulum indicator 5| is a function of the rate at which the turn is negotiated, with the result that the pendulum indicator 5| not only indicates whether or not the ship is turning, but it also gives a reliable reading in terms of severity of turn.

In order to facilitate the pilots observation of the instrument to ascertain direction and severity of turn I prefer to provide indicia 9| on the transparent front 68 of the casing 52, and whereas these indicia may take the form of callbrations to aid in the reading of the actual severity of turn, the preferred construction employs only the initials L R. It is believed that under most circumstances of aerial navigation the severity of turn can be ascertained with sufficient accuracy merely by observation of the approximateangularity of the pendulum indi- 4 cator with respect to the vertical without having to bother about making comparison of positions of the needle with a series of calibrations. The pilots ready observation of the position of the pendulum indicator 5| to ascertain whether it is in its zero-reading position or displaced therefrom, and if displaced, to what extent, is facilitated by providing a reference mark in association with the pendulum indicator 5!. This reference mark may conveniently take the form of a single mark 92 on the front of the housing 53, preferably of such shape and so arranged that it appears to be a continuation of the upper end of the pendulum indicator 5| when that indicator is in its zero-reading position. As a result, even the slightest deviation of the indicator 5! from its zero-reading position is immediately apparent because of the ensuing misalignment of both side edges of the pendulum indicator with the corresponding side edges of the mark 92.

The instrument also includes a gyroscopically stabilized reference, the function of which is to give the pilot a ready indication of whether his ship is experiencing any lateral inclination. The cylindrical shell 53 of the chamber 52 is providel with a diametrically extending rib 95 disposed in front of the transparent window 68. This rib 96 provides a journal support for a pin 91 upon the forward end of which a reference, or indicator 98 is secured. Preferably this indicator 98 is shaped to provide a miniature Wing and fuselage portion |0| so that it simulates the appearance of the forward portion of an airplane viewed from directly astern. Whereas the indicator 98 is free to rotate about the axis of the pin 91, means are provided for retaining the indicator 98 with thewings 99 of the indicator parallel to the wings of the actual airplane. The indicator 98 is formed of suitable magnetic material; and mounted rigidly within the main housing l6 are preferably a pair of magnets I02 (Fig. 1). These magnets are arranged on opposite sides of chamber 52 and with their longest dimensions extending vertically; and since it is desirable in the present construction that they be magnetized transversely it is preferred that magnets composed of aluminum, cobalt and nickel be employed, since the' use of this combination of metals in the manufacture of a magnet facilitates such a transverse magnetization. Actually, therefore, the indicator 99 is an armature retained in pre-selected position with respect to the airplane by its controlling magnets I02 with the result that regardless of the position of transverse inclination assumed by the airplane, the indicator 93 will be held by the magnets N12. to corresponding position. By comparison of indicator 88 and line H there is conveyed instantly to the pilot a reliable indication of whether or not the ship is laterally inclined and if so, to what extent. Figures 4 and 5 show the indicator as in a position wherein it shows that the airplane is laterally inclined whereas Figures 1, 2, 3, and 6 show the device indicating that the ship is disposed with its wings horizontal.

An important feature of this portion of my invention lies in the" fact that the wing-simulating indicator is and the pendulum indicator 5| both move about a common axis and are" in superimposed relationship, since' this arrangement thereof makes them appear to the pilot that they intersect each other. This detail makes possible the instant comparison of the respective positions of these two indicators and the amply accurate estimation of the angularity therebetween. As a consequence, the pilot can instantly be apprised of whether or not his ship is being banked at the angularity appropriate to the turn then being negotiated. Even though the pilot were to glance at the instrument in the utmost haste and with his mind preoccupied with other matters, the lack of perpendicularity between the two i idicators 5! and 538 would instantly be so obvious to the pilot that it would operate as a warning signal, informing him that an error is being committed in the manner in which the ship is being flown, and that some correction is required. The nature and extent of the necessary correction also are shown by the instrument and are impressed upon the pi'lots consciousness with almost equal speed. Since the lower end [M of the indicator 5! is enlarged to present the appearance of a round weight such as that with which the most familiar type of pendulum ordinariiy is provided, the indicator actually looks like a pendulum; and since the movements: of the indicator 5 l correspond to those which a real pendulum would maize under similar circumstances, the" pilot is made to realize the actual conditions of flight which are responsible for the indicator 5i having taken a certain position, with a minimum of mental effort.

For example, Figure 6' shows the effect upon the instrument of the ship having been put into a turn without being correspondingly banked. The oblique position of the pendulum indicator 5i shows that the ship is turning, and since what appears to be its weighted lower end is thrown to the right the pilot is enabled to realize in stantly that the ship is turning to the left. Furthermore it is equally apparent that the ship should be banked by raising the starboard wing tip, until perpendicularity reestablished between the in icators 5i and st; in order to place the ship in the properly banked position as determined by the severity of the turn which the ship is experiencing and which accounts for the oblique position of the pendulum indicator 5i.

In Figure 5, on the other hand, the pendulum indicator Ell is disposed vertically, showing that the ship is trave. 1g straight ahead, while the wing-simulating indicator as is tilted with its port side lowered, thus showing that the ship is correspondingly tilted. Instantly upon glancing at the instrument, and without having to read calibrations or otherwise to exert any con scious effort, the pilot ismade to realize that the port wing tip should be raised if. he is to avoid side slip which might, prove to'be'dangerous.

Figure 4 illustrates the condition of the instrument while the ship is in a properly banked turn. That" both the direction and the degree of banking are appropriate, respectively, to the direction and rate: of turn is instantly apparent. because oi the fact that the condition of perpendicularity between. the two indicators 51 and 98 is soreadily apparent;

Means also are provided in the flight indicator of the present invention for indicating pitch, i. e., whether or not the ship is in level flight, or if it is either climbing or descending; Since the wing-simulating indicator 98 is. carried by structure which is rigid with. the rotor-bearing casing 36, and since this structure is a part of that which is stabilized by the gyro vertical 42, the housin it of the instrument will move in rotary motion about the minor gimbal axis with respect to the stabilized portion. of the instrument when the ship carrying the instrument experiences any pitching maneuver. However, since the entire housing 53 of. the chamber 52 on which the wing-simulating indicator 8% is mounted also is stabilized, it is necessary, in order for the pilot to determine pitch, for him to observe the position of the indicator 98 with respectto the center of the window 2i through which the indicating media 22 are observed. Accordingly, a second zero-indicating reference mark I'll is provided, this mark Hi being ca ried by the housing it with the result that it moves vertically with respect to the wing-simulating. indicator 93 when pitch occurs. The preferable form for this mark ill! is that of a miniature simulation of the tail structure of' an airplane, its size being proportionate. to that of the wing-simulating indicator 9% so that the two indicators Q8 and iii cooperate with each other in presenting a rather close simulation of the appearance of a complete airplane viewed from directly astern,

Consequently the roll and pitch indicating media of the present instrument correspond closely both in appearance and. mode of operation to the corresponding. indicators of the gyroscopic instrument which forms the subject matter of my co-pending application, Serial Number 457,730, now Patent No. 2,423,269. Since the wing-simulating indicator 9% is stabilized by the gyroscope zsagainstpitching any pitching movement of the ship will cause the reference mark 2 ii to move vertically with respect to the wingsimulating indicator 9%; so that when theship noses up the wing-simulating indicator 93 will be higher than the reference mark Iii as illus trated in Figure 2 with the result that the. two indicator-stogether closely resemble an actual picture of the shiptaken from asternand projected the instrument panel for the pilots ready observation and showing the forward portion of the miniature replica of the plane actually higher than the tail portion thereof. Similarly with respect to Figure 3 wherein the forward or wing-simulating portion 98 is lower than the mark iii or tail simulating portion, a position which will be assumed when the shi is in a nose down attitude. The mark Ill includes a transversely extending portion H2 corresponding to the horizontal rudder of a plane and a portion H3 extending vertically upwards from the cen ter thereof corresponding tothe vertical rudder. ince the vertical portion H3 overlies the pendulumindicator 5% and since it is at all times perpendicular to the wing-simulating indicator 98-, it further facilitates observation of any deviation from true perpendicularity between" the pen- I 9 dulum indicator and the wing-simulating indicator 98, for' the purpose of determining whether or not the ship is banking appropriately to the severity of turn being negotiated, as explained hereinabove.

However, the vertical portion H3 also affords great convenience when observed without making any comparison thereof with the pendulum indicator. Any deviation of this portion I I? from truly vertical position is very readily disc-ernable even though such deviation may be slight, regardless of the position of the pendulum indicator 5|, this follows from the fact that the reference mark 92 is maintained by the gyro vertical 42 in position vertically above the axis about which the indicator Ill rotates in accordance with lateral inclination of the ship. Accordingly when the vertical portion H3 of the indicator H! does not point accurately at the reference mark 92, for example, as illustrated in Figures 4 and 5 lateral tilting of the ship is indicated.

Whereas in Figures 1 to 6, inclusive, the tailsimulating reference mark H2 is carried by the transparent window 2| and hence is rigid with respect to the main housing l6 of the instrument, Figure 7 illustrates a modified form of support for the tail-simulating indicator wherein it is vertically adjustable. Under certain conditions of flight circumstances may arise which might make it desirable to shift the indicator l2] vertically so that its zero-reading position is other than at the exact center of the window 2|. For example, the ship might be so loaded that it is somewhat out of trim, i. e., it is either nose-heavy or tail-heavy and consequently must fly in a different position with respect to the horizontal in order to maintain level flight. Having the tail-simulating indicator l2! vertically adjustable permits the pilot to compensate for such unusual loading conditions by placing the indicator l2! in that position in which it is aligned with the Wing-simulating indicator 98 when the ship is in horizontal flight.

Toward this end. the indicator I2I, instead of being fastened to the transparent window 2i, is carried by a transversely extending and preferably transparent bar I22. This bar is mounted for vertical adjustment but instead of being mounted for planar movement it is movable in an arc the center of which lies in the minor gimbal'axis of the gyroscope, i. e., in the axis of the pins .33 and 34. Consequently the transparent bar I22 is rigidly secured to and interconnects a pair of arms I23 each of which is pivotally mounted as by a pin 124 revolubly seated in a bushing I26 which is rigid with the main housing is. These two bushings I26 are oppositely disposed in the sides of the housing It and within the plane of movement of the axis of the pins 33 and 34. Hence when the indicator I2! is adjusted vertically it moves in an arcuate path about the same axis as that about which the housing I6 moves with respect to the gyroscopically stabilized mechanism when the ship carrying the instrument pitches. Means are provided for manually shifting the indicator 12!. A convenient form of such mechanism is a revoluble stem l3! extending through the front wall of the housing l5 and having a manually rotatable head 32 on its exposed end. The inner'end of the stem l3! carries a disc I33 having a notch use in one side thereof within which a pin 353 is seated and since this pin 136 is rigid with the transparent bar I22, rotation of the '10 head I32 of the stem l3! results in vertical movement of the indicator HI.

I claim:

1.'A flight indicating instrument for aircraft comprising, in combination, an indicator housing for mounting on an aircraft; a gyro-vertical universally mounted in said indicator housing; a cylindrical housing member movable with and stabilized by said gyro-vertical; a pendulum indicator mounted in said housing member for pivotal movement in a transverse plane in response to transverse acceleration forces; and means in said housing member operative to dampen oscillations of said pendulum indicator.

2. A flight indicating instrument for aircraft comprising, in combination, an indicator housing for mounting on an aircraft; a gyro-vertical universally mounted in said indicator housing;

a cylindrical housing member movable with and stabilized by said gyro-vertical; a pendulum indicator mounted in said housing member for pivotal movement in a transverse plane in response to transverse acceleration forces; a pair of relatively vertical movable aircraft attitude indicators cooperatively associated with said pendulum indicator, one of said attitude indicators being fixed relative to the aircraft and the other being secured for movement in a vertical plane with said housing member, to simulate pitching of the aircraft.

3. A flight indicating instrument for aircraf comprising, in combination, an indicator housing for mounting on an'aircraft; a' gyro-vertical universally mounted in said indicator housing; a cylindrical housing member movable with and stabilized by said gyro-vertical; a pendulum indicator mounted in said housing member for pivotal movement in a transverse plane in response to transverse acceleration forces; and a pair of relatively vertically movable aircraft attitude indicators cooperatively associated with said pendulum indicator, one of said attitude indicators being fixed relaitve to the aircraft and the other being secured for movement in a vertical plane with said housing member to simulate pitching of the aircraft; both of said attitude indicators being oscillatable about the longitudinal axis of the aircraft to simulate banking of the latter.

4. A flight indicating instrument for aircraft comprising, incombination, anindicator housing for mounting on an aircraft; a gyro-vertical universally mounted in said indicator housing; a cylindrical housing member movable with and stabilized by said gyro-vertical, the axis of said housing member being parallel to the longitudinal axis of the aircraft; a transparent indicatin face member mounted at the forward end of said housing member; an opaque circular partition mounted intermediate the ends of said housing member; an'axial shaft pivotally mounted in said housing member and extending through said partition; a pendulous weight secured to said shaft behind said partition for pivotal movement in a transverse plane in response to transverse acceleration forces; a pendulum indicator secured to said shaft between said face member and said partition to indicate such transverse acceleration forces; and means in said housing member operative to dampen oscillations of said pendulous weight.

5. A flight indicating instrument for aircraft comprising, in combination, an indicator housing for mounting on an aircraft; a gyro-vertical universally mounted in said indicator housing; a cylindrical housing member movable with and sta bilized by said gyro-vertical, the axis .of said housing member being parallel to the longitudinal axis of the aircraft; a transparent indicating face member mounted at the forward end of said housing member; an opaque circular partition mounted intermediate the ends of said housing member; an axial shaft pivotally mounted in said housing member and extending through said partition; a pendulous weight secured to said shaft behind said partition for pivotal movement in a transverse plane: in response'to transverse acceleration forces; a pendulum indicator secured to said shaft between said face member and said partition to indicate such transverse acceleration forces; means in said housing member operative to dampen oscillations of said pendulous weight; an aircraft attitude indicator pivotally mounted on said housing member in front of said face member for oscillation in a transverse plane; and means movable with said housing and operative to oscillate said attitude indicatorto simulate banking of the aircraft.

6, A flight indicating instrument for aircraft comprising, in combination, an indicator housing for mounting on an aircraft; a gyro-vertical universally mounted in said indicator housing; a cylindrical housing member movable with and stabilized by said gyro-vertical, the axis of said housing member being parallel to the longitudinal axis of the aircraft; a transparent indicating face member mounted at the forward end of said housing member; an opaque circular partition mounted intermediate the ends of said housing member; an axial shaft pivotally mounted in said housing member and extending through said partition; a pendulous weight secured to said shaft behind said partition for pivotal movement in a transverse plane in response to acceleration forces; a pendulum indicator secured to said shaft between said face member and said partition to indicate such transverse acceleration forces; means in said housing member operative to dampen oscillations of said pendulous weight; an aircraft attitude indicator pivotally mounted on said housing member in front of said face member for oscillation in a transverse plane; means movable withsaid housing and operative to oscillate said attitude indicator to simulate banking of the aircraft; and a second attitude indicator secured to said housing and arranged adjacent said first attitude indicator and movable vertically relative thereto, to simulate pitch ing of the aircraft.

7. A flight indicating instrument for aircraft comprising, in combination, an indicator housing for mounting on an aircraft; a gyro-vertical universally mounted in said indicator housing; a cylindrical housing member movable with and stabilized by said gyro-vertical, the axis of said housing member being parallel to the longitudinal axis of the aircraft; a transparent indicating face member mounted at the forward end of said housing member; an opaque circular partition. mounted intermediate the ends of said housing member; an axial shaft pivotally mounted in said housing member and extending through said partition; a pendulous weight secured to said shaft behind said partition for pivotal movement in a transverse plane in response to transverse acceleration forces; a pendulum indicator secured to said shaft between said face member and said partition to indicate such transverse acceleration forces; means in said housing member operative to dampen oscillation of said pendulous weight; an aircraft attitude indicator pivotally mounted on said housing member in front of said face member for oscillation in a transverse plane; means movable with said housing and operative to oscillate said attitude indicator to simulate banking of the aircraft; a second attitude indicator adjustably secured to said housing and arranged adjacent said first attitude indicator and movable vertically relative thereto to simulate pitching of the aircraft; and means for adjusting said second indicator to align said attitude indicators when the aircraft is in its normal fore and aft flight attitude.

THOMAS O. SUMMERS, J'R.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES. PATENTS Number Name Date 1,433,102 Sparry Oct. 24, 1922 1,706,201 Drexler Mar. 19, 1929 1,732,397 Braibant Oct. 22, 1929 1,903,710 Stohr Apr, 11, 1933 2,141,555 Reid Dec. 27, 1938 FOREIGN PATENTS Number Country Date 145,459 British Apr. 21, 1921 145,460 British Oct. 18, 1921 474,694 German Apr. 9, 1929 

